Large trucks such as dump trucks used in interstate commerce are required by law to be provided with mud flaps behind each set of rear wheels. Such flaps are required to protect other vehicles and persons from rocks and other debris from being rearwardly ejected from the truck wheels. Such flaps often can be torn from the rear of the vehicle when it is either backed into some object, or in the case of a dump truck, when the flap is buried by the load being deposited from the dump truck, the resultant lack of a proper mud flap on many vehicles, thus, gives rise to injuries and property damage.
Various flap retraction systems have been heretofore proposed. Many such systems, however, attempt to raise only the rear of the flap by folding the flap in half. Many of these systems require the use of complex and easily damaged actuating systems such as springs and cables. See, for example, U.S. Pat. Nos. 582,109; 3,248,126; and 3,905,616. The other system entails the provision of a removable mud flap suspended on a hanger. See, for example, U.S. Pat. No. 3,934,901. Such systems, however, require that the operator physically remove the mud flaps after leaving the truck cab. Another removable mud flap system is shown in U.S. Pat. No. 3,877,722.
Retractable mud flaps have also been proposed, however, such systems in the past have involved a series of springs and cables, all of which cause trouble for the operator and, thus, have not come into widespread usage. See U.S. Pat. Nos. 2,721,760 and 2,857,200.